Update the infrastructure for single result specifications. (#272)

* Added new contracts and base classes for single result specifications.

* Updated repository with verbose methods. Marked GetBySpec methods as obsolete.

* Removed the constraint for GetBySpec method.

* Added UpdateRangeAsync repository method.

* Update XML comment.

Specification.EntityFramework6/src/Ardalis.Specification.EntityFramework6/RepositoryBaseOfT.cs

@@ -34,6 +34,7 @@ public virtual async Task<T> AddAsync(T entity, CancellationToken cancellationTo
 
       return entity;
     }
+
     /// <inheritdoc/>
     public virtual async Task<IEnumerable<T>> AddRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
     {
@@ -51,14 +52,26 @@ public virtual async Task UpdateAsync(T entity, CancellationToken cancellationTo
 
       await SaveChangesAsync(cancellationToken);
     }
-
+
+    /// <inheritdoc/>
+    public virtual async Task UpdateRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
+    {
+      foreach (var entity in entities)
+      {
+        dbContext.Entry(entity).State = EntityState.Modified;
+      }
+
+      await SaveChangesAsync(cancellationToken);
+    }
+
     /// <inheritdoc/>
     public virtual async Task DeleteAsync(T entity, CancellationToken cancellationToken = default)
     {
       dbContext.Set<T>().Remove(entity);
 
       await SaveChangesAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
     public virtual async Task DeleteRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
     {
@@ -78,29 +91,59 @@ public virtual async Task<T> GetByIdAsync<TId>(TId id, CancellationToken cancell
     {
       return await dbContext.Set<T>().FindAsync(cancellationToken: cancellationToken, new object[] { id });
     }
+
     /// <inheritdoc/>
-    public virtual async Task<T> GetBySpecAsync<Spec>(Spec specification, CancellationToken cancellationToken = default) where Spec : ISpecification<T>, ISingleResultSpecification
+    [Obsolete]
+    public virtual async Task<T> GetBySpecAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
     {
       return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
+    [Obsolete]
     public virtual async Task<TResult> GetBySpecAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
     {
       return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
     }
 
+    /// <inheritdoc/>
+    public virtual async Task<T> FirstOrDefaultAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<TResult> FirstOrDefaultAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<T> SingleOrDefaultAsync(ISingleResultSpecification<T> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).SingleOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<TResult> SingleOrDefaultAsync<TResult>(ISingleResultSpecification<T, TResult> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).SingleOrDefaultAsync(cancellationToken);
+    }
+
     /// <inheritdoc/>
     public virtual async Task<List<T>> ListAsync(CancellationToken cancellationToken = default)
     {
       return await dbContext.Set<T>().ToListAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
     public virtual async Task<List<T>> ListAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
     {
       var queryResult = await ApplySpecification(specification).ToListAsync(cancellationToken);
 
       return specification.PostProcessingAction == null ? queryResult : specification.PostProcessingAction(queryResult).ToList();
     }
+
     /// <inheritdoc/>
     public virtual async Task<List<TResult>> ListAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
     {
@@ -143,6 +186,7 @@ protected virtual IQueryable<T> ApplySpecification(ISpecification<T> specificati
     {
       return specificationEvaluator.GetQuery(dbContext.Set<T>().AsQueryable(), specification, evaluateCriteriaOnly);
     }
+
     /// <summary>
     /// Filters all entities of <typeparamref name="T" />, that matches the encapsulated query logic of the
     /// <paramref name="specification"/>, from the database.

Specification.EntityFrameworkCore/src/Ardalis.Specification.EntityFrameworkCore/RepositoryBaseOfT.cs

@@ -34,6 +34,7 @@ public virtual async Task<T> AddAsync(T entity, CancellationToken cancellationTo
 
       return entity;
     }
+
     /// <inheritdoc/>
     public virtual async Task<IEnumerable<T>> AddRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
     {
@@ -51,14 +52,23 @@ public virtual async Task UpdateAsync(T entity, CancellationToken cancellationTo
 
       await SaveChangesAsync(cancellationToken);
     }
-
+
+    /// <inheritdoc/>
+    public virtual async Task UpdateRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
+    {
+      dbContext.Set<T>().UpdateRange(entities);
+
+      await SaveChangesAsync(cancellationToken);
+    }
+
     /// <inheritdoc/>
     public virtual async Task DeleteAsync(T entity, CancellationToken cancellationToken = default)
     {
       dbContext.Set<T>().Remove(entity);
 
       await SaveChangesAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
     public virtual async Task DeleteRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default)
     {
@@ -78,29 +88,59 @@ public virtual async Task<int> SaveChangesAsync(CancellationToken cancellationTo
     {
       return await dbContext.Set<T>().FindAsync(new object[] { id }, cancellationToken: cancellationToken);
     }
+
     /// <inheritdoc/>
-    public virtual async Task<T?> GetBySpecAsync<Spec>(Spec specification, CancellationToken cancellationToken = default) where Spec : ISpecification<T>, ISingleResultSpecification
+    [Obsolete]
+    public virtual async Task<T?> GetBySpecAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
     {
       return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
+    [Obsolete]
     public virtual async Task<TResult?> GetBySpecAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
     {
       return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
     }
 
+    /// <inheritdoc/>
+    public virtual async Task<T?> FirstOrDefaultAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<TResult?> FirstOrDefaultAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).FirstOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<T?> SingleOrDefaultAsync(ISingleResultSpecification<T> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).SingleOrDefaultAsync(cancellationToken);
+    }
+
+    /// <inheritdoc/>
+    public virtual async Task<TResult?> SingleOrDefaultAsync<TResult>(ISingleResultSpecification<T, TResult> specification, CancellationToken cancellationToken = default)
+    {
+      return await ApplySpecification(specification).SingleOrDefaultAsync(cancellationToken);
+    }
+
     /// <inheritdoc/>
     public virtual async Task<List<T>> ListAsync(CancellationToken cancellationToken = default)
     {
       return await dbContext.Set<T>().ToListAsync(cancellationToken);
     }
+
     /// <inheritdoc/>
     public virtual async Task<List<T>> ListAsync(ISpecification<T> specification, CancellationToken cancellationToken = default)
     {
       var queryResult = await ApplySpecification(specification).ToListAsync(cancellationToken);
 
       return specification.PostProcessingAction == null ? queryResult : specification.PostProcessingAction(queryResult).ToList();
     }
+
     /// <inheritdoc/>
     public virtual async Task<List<TResult>> ListAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default)
     {
@@ -143,6 +183,7 @@ protected virtual IQueryable<T> ApplySpecification(ISpecification<T> specificati
     {
       return specificationEvaluator.GetQuery(dbContext.Set<T>().AsQueryable(), specification, evaluateCriteriaOnly);
     }
+
     /// <summary>
     /// Filters all entities of <typeparamref name="T" />, that matches the encapsulated query logic of the
     /// <paramref name="specification"/>, from the database.

Specification/src/Ardalis.Specification/IReadRepositoryBase.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -32,7 +33,8 @@ public interface IReadRepositoryBase<T> where T : class
     /// A task that represents the asynchronous operation.
     /// The task result contains the <typeparamref name="T" />, or <see langword="null"/>.
     /// </returns>
-    Task<T?> GetBySpecAsync<Spec>(Spec specification, CancellationToken cancellationToken = default) where Spec : ISingleResultSpecification, ISpecification<T>;
+    [Obsolete]
+    Task<T?> GetBySpecAsync(ISpecification<T> specification, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Finds an entity that matches the encapsulated query logic of the <paramref name="specification"/>.
@@ -43,8 +45,53 @@ public interface IReadRepositoryBase<T> where T : class
     /// A task that represents the asynchronous operation.
     /// The task result contains the <typeparamref name="TResult" />.
     /// </returns>
+    [Obsolete]
     Task<TResult?> GetBySpecAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// Returns the first element of a sequence, or a default value if the sequence contains no elements.
+    /// </summary>
+    /// <param name="specification">The encapsulated query logic.</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
+    /// <returns>
+    /// A task that represents the asynchronous operation.
+    /// The task result contains the <typeparamref name="T" />, or <see langword="null"/>.
+    /// </returns>
+    Task<T?> FirstOrDefaultAsync(ISpecification<T> specification, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Returns the first element of a sequence, or a default value if the sequence contains no elements.
+    /// </summary>
+    /// <param name="specification">The encapsulated query logic.</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
+    /// <returns>
+    /// A task that represents the asynchronous operation.
+    /// The task result contains the <typeparamref name="TResult" />, or <see langword="null"/>.
+    /// </returns>
+    Task<TResult?> FirstOrDefaultAsync<TResult>(ISpecification<T, TResult> specification, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.
+    /// </summary>
+    /// <param name="specification">The encapsulated query logic.</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
+    /// <returns>
+    /// A task that represents the asynchronous operation.
+    /// The task result contains the <typeparamref name="T" />, or <see langword="null"/>.
+    /// </returns>
+    Task<T?> SingleOrDefaultAsync(ISingleResultSpecification<T> specification, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.
+    /// </summary>
+    /// <param name="specification">The encapsulated query logic.</param>
+    /// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
+    /// <returns>
+    /// A task that represents the asynchronous operation.
+    /// The task result contains the <typeparamref name="TResult" />, or <see langword="null"/>.
+    /// </returns>
+    Task<TResult?> SingleOrDefaultAsync<TResult>(ISingleResultSpecification<T, TResult> specification, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Finds all entities of <typeparamref name="T" /> from the database.
     /// </summary>

Specification/src/Ardalis.Specification/IRepositoryBaseOfT.cs → Specification/src/Ardalis.Specification/IRepositoryBase.cs

@@ -23,6 +23,7 @@ public interface IRepositoryBase<T> : IReadRepositoryBase<T> where T : class
     /// The task result contains the <typeparamref name="T" />.
     /// </returns>
     Task<T> AddAsync(T entity, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Adds the given entities in the database
     /// </summary>
@@ -33,24 +34,36 @@ public interface IRepositoryBase<T> : IReadRepositoryBase<T> where T : class
     /// The task result contains the <typeparamref name="IEnumerable<T>" />.
     /// </returns>
     Task<IEnumerable<T>> AddRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Updates an entity in the database
     /// </summary>
     /// <param name="entity">The entity to update.</param>
     /// <returns>A task that represents the asynchronous operation.</returns>
     Task UpdateAsync(T entity, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Updates the given entities in the database
+    /// </summary>
+    /// <param name="entities">The entities to update.</param>
+    /// <param name="cancellationToken"></param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    Task UpdateRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Removes an entity in the database
     /// </summary>
     /// <param name="entity">The entity to delete.</param>
     /// <returns>A task that represents the asynchronous operation.</returns>
     Task DeleteAsync(T entity, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Removes the given entities in the database
     /// </summary>
     /// <param name="entities">The entities to remove.</param>
     /// <returns>A task that represents the asynchronous operation.</returns>
     Task DeleteRangeAsync(IEnumerable<T> entities, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Persists changes to the database.
     /// </summary>

Specification/src/Ardalis.Specification/ISingleResultSpecification.cs

@@ -2,9 +2,27 @@
 {
   /// <summary>
   /// A marker interface for specifications that are meant to return a single entity. Used to constrain methods
-  /// that accept a Specification and return a single result rather than a collection of results
+  /// that accept a Specification and return a single result rather than a collection of results.
   /// </summary>
   public interface ISingleResultSpecification
   {
   }
+
+  /// <summary>
+  /// Encapsulates query logic for <typeparamref name="T"/>. It is meant to return a single result.
+  /// </summary>
+  /// <typeparam name="T">The type being queried against.</typeparam>
+  public interface ISingleResultSpecification<T> : ISpecification<T>, ISingleResultSpecification
+  {
+  }
+
+  /// <summary>
+  /// Encapsulates query logic for <typeparamref name="T"/>,
+  /// and projects the result into <typeparamref name="TResult"/>. It is meant to return a single result.
+  /// </summary>
+  /// <typeparam name="T">The type being queried against.</typeparam>
+  /// <typeparam name="TResult">The type of the result.</typeparam>
+  public interface ISingleResultSpecification<T, TResult> : ISpecification<T, TResult>, ISingleResultSpecification
+  {
+  }
 }

Specification/src/Ardalis.Specification/SingleResultSpecification.cs

@@ -0,0 +1,12 @@
+namespace Ardalis.Specification
+{
+  /// <inheritdoc cref="ISingleResultSpecification{T}"/>
+  public class SingleResultSpecification<T> : Specification<T>, ISingleResultSpecification<T>
+  {
+  }
+
+  /// <inheritdoc cref="ISingleResultSpecification{T, TResult}"/>
+  public class SingleResultSpecification<T, TResult> : Specification<T, TResult>, ISingleResultSpecification<T, TResult>
+  {
+  }
+}